Injecting fluid medicaments into internal tissues of the body (e.g. the myocardium) can be problematic. This is particularly so due to the fact there is no way for the surgeon to have a direct visualization of the injection site. Although indirect visualization techniques, such as fluoroscopy, can significantly aid in advancing an injection needle to the intended injection site, additional control at the site may be required in order to properly insert a needle into tissue for a precise injection. For instance, control over the depth to which an injection needle is inserted into the tissue may be a crucial consideration. Further, and specific to the heart, perforation of the catheter tip through the heart wall causes blood to leak into the pericardial sack, which can be fatal.
As a practical matter, a reliance on extracorporeal control over an injection needle, for the specific purpose of precisely attaining a desired depth of needle insertion into tissue, is complicated by several factors. Not the least of these involves the proper positioning of the injection needle at the target tissue site, before needle insertion. Typically, such a pre-positioning of an injection needle can be successfully accomplished using a positioning catheter that incorporates radiopaque markers (e.g. fluoroscopy). Nevertheless, this pre-positioning relies on only indirect visual indicators that may fail to provide sufficient control for inserting the needle into target tissue.
In light of the above, it is an object of the present invention to provide a system and method for performing an injection of fluid medicament into a target tissue of a patient that provides for tactile indications of a proper needle insertion. Another object of the present invention is to ensure that such a needle insertion is performed to within a precise depth into the target tissue and to prevent perforation of the tissue by the catheter tip. Still another object of the present invention is to provide a system and method for performing an injection of fluid medicament into a target tissue that is relatively simple to manufacture, is easy to use, and is comparatively cost effective.